1. Field of the Invention
The present invention relates to expansion device such as a PC card slot, and a computer system to which the expansion device can be connected.
2. Description of the Related Art
Conventional expansion devices for a personal computer include a PC card slot, a printer port, a serial communication port, and the like. Note that the PC card slot is an expansion slot for PC cards, which is based on the standards of PCMCIA (Personal Computer Memory Card International Association). In using expansion devices, each device is detachably connected to a computer body through a dedicated connector. The computer body has a plurality of types of body-side connectors corresponding to the dedicated connectors for various expansion devices.
The computer body includes an I/O controller (mainly constituted by a gate array) for controlling input/output processing of interface signals between the above expansion devices and the CPU in the computer. The I/O controller is connected to the PC card slot, the printer port, and the serial communication port through the respective connectors mounted in the computer body.
In a personal computer which can use expansion devices, since input/output control of interface signals is performed by the I/O controller in the computer body as described above, the I/O controller respectively assigns interface signals through the individual connectors arranged for the respective expansion devices.
For example, a dedicated connector having 68 pins is provided for the PC card slot, and the I/O controller has 68 input/output pins for interface signals. Similarly, 25 input/output pins for interface signals are arranged for the printer port, and 9 input/output pins for interface signals are arranged for the serial communication port.
As the number of types of expansion devices increases, therefore, the number of input/output pins of the I/O controller increases, resulting in increases in the size and cost of an IC package constituting a gate array. In addition, the computer body has connectors corresponding to the dedicated connectors of the respective expansion devices. For this reason, with an increase in the number of connectors, the space required to mount the connectors increases. Since the space required to mount connectors is limited especially in a compact personal computer such as a notebook computer, it is difficult to use a plurality of types of expansion devices.